Effects of occlusal splint and exercise therapy, respectively, for the painful temporomandibular disorder in patients seeking for orthodontic treatment: a retrospective study

Effect of Various Degrees of Anterior Disc Displacement on the Biomechanical Response of the Masticatory System

Anterior disc displacement (ADD) is one of the most prevalent temporomandibular disorders (TMD). It was widely recognized that occlusal factors could affect temporomandibular joint (TMJ). However, the impacts of ADD on the biomechanical environment of TMJ and occlusion are still unclear. This study aimed to describe the effects of ADD on the masticatory system, including TMJ and occlusion. The finite element model (FEM) was constructed based on the medical images of a healthy adult male. The complete skull, masticatory muscles, TMJs, and related ligaments were included. Three FEMs with different degrees of ADD were constructed with disc-condyle angles of 10 deg, 20 deg, and 30 deg. The muscle forces corresponding to intercuspal clenching (ICC) were applied as the loading condition. Four models were conducted: normal, mild, moderate, and severe ADD. It was found that the overall stress distribution was relatively consistent across the four models. The contact stress on the TMJ and occlusion in severe ADD was visibly different from the other three models. In addition, the contact stress on the condyle gradually increased with the increasing occlusal strength. Abnormally high-stress concentration began to appear on the condyle at 30% muscle strength. Moderate ADD was more of a transitional stage. Compared to mild and moderate ADD, severe ADD had visibly effects on the stress response of the TMJ and the entire mandible (including occlusion), such as abnormally high stresses of the condyle, stress concentration on the second molar, and prone to disc extrusion and anterior slippage during high-strength occlusion.

Occlusal splint or botulinum toxin-a for jaw muscle pain treatment in probable sleep bruxism: A randomized controlled trial

OBJECTIVES

To conduct an equivalency randomized controlled trial comparing occlusal splint (OS) and botulinum toxin-A (BTX-A) on jaw muscle pain in probable sleep bruxism.

METHODS

Sixty patients (≥18 years, probable sleep bruxism, and jaw muscle pain) were randomly allocated into groups. The primary outcome was the reduction of jaw muscle pain, assessed using the Graded Chronic Pain Scale (GCPS, v2.0). Secondary outcomes included: parameters of jaw opening and mandibular mobility; distribution of muscle pain; Jaw Functional Limitation Scale-20 (JFLS-20), Oral Behaviors Checklist (OBC); and Oral Health Impact Profile-14 (OHIP-14). Only the evaluator was blinded. Multilevel mixed-effects regression models were used.

RESULTS

Fifty-nine patients (30 received OS and 29 BTX-A) were analyzed at baseline, 3 and 6 months follow-up. One patient dropped out after receiving the intervention. No differences between the interventions were observed concerning the GCPS (p = 0.627), although a significant reduction was observed at 3 (OR=13.26, 95%CI[6.61-26.59]) and 6 months (OR=12.36, 95%CI[4.93-30.98]), regardless of the treatment. BTX-A showed a lower score reduction on JFLS-20 than OS (OR=0.29, 95%CI[0.11-0.82]). BTX-A presented inferior results for the parameters: opening without pain(p = 0.045), unassisted maximum opening(p = 0.024), assisted maximum opening(p = 0.041), and protrusion(p = 0.016). An improvement in OHIP-14 scores was observed at 3 (IRR=1.08, CI95%[1.02-1.14]) and 6 months (IRR=1.10, CI95%[1.04-1.16]), regardless of the intervention. BTX-A participants(n = 23;79,3%) reported mild discomfort during chewing.

CONCLUSION

OS and BTX-A can effectively decrease the GCPS scores, improve OHRQoL, and enhance functional outcomes in sleep bruxist patients with jaw muscle pain. OS demonstrated slight advantages in specific parameters.

CLINICAL SIGNIFICANCE

Both occlusal splints and botulinum toxin-A effectively reduce jaw muscle pain in bruxist patients, improving quality of life and mandibular function. Clinically, occlusal splints may offer additional benefits in specific functional parameters. (NCT03456154).

Occlusal interventions for managing temporomandibular disorders

BACKGROUND

Temporomandibular disorders (TMD) are conditions related to the musculoskeletal structure of the temporomandibular joint, which may lead to muscle or joint pain and other health issues. TMD may present in muscles only (myogenous), joints only (arthrogenous), or both (mixed), and may affect one side or both sides of the face. Myogenous TMD may present with or without limited mouth opening. Arthrogenous TMD may present as disc displacement with or without reduction ('reduction' meaning the articular disc resumes its normal position when the jaw is moving). Occlusal interventions change the occlusal relationship of maxillary and mandibular teeth to improve the alignment of the tooth contact, with the aim of relieving pain, and improving psychosocial functioning and quality of life. Occlusal interventions include splints and adjustments. Occlusal splints are specially designed mouth guards; they are generally classified as stabilisation, reflex or repositioning splints. Occlusal adjustment is the grinding down of teeth to improve occlusion.

OBJECTIVES

To assess the effects of occlusal interventions in people diagnosed with temporomandibular disorders (TMD), compared to other interventions or no treatment, on joint pain, muscle pain at rest and when chewing, quality of life, discomfort, and recurrence.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched following sources up to 9 August 2022: Cochrane Oral Health's Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE via Ovid, Embase via Ovid, and two trials registers.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of occlusal interventions (splints or adjustment) for managing TMD compared with no treatment, placebo, occlusal splint with a different mechanism of action, or other active treatments.

DATA COLLECTION AND ANALYSIS

We adopted standard Cochrane methods to select studies, extract and analyse data, assess the risk of bias in the studies, and judge the certainty of the evidence. We reported outcomes as short term (three months or less) or long term (more than three months).

MAIN RESULTS

We included 57 studies (2846 participants) that compared occlusal splints with no treatment, placebo, or another treatment. Most of the studies evaluated full hard stabilisation splint (FHSS) as the occlusal splint. We judged only one study to be at low risk of bias. Our key outcomes of interest were self-reported joint pain when chewing, muscle pain at rest and when chewing, discomfort, severity and frequency of joint noise, and recurrence rate. The duration of the studies ranged from 5 weeks to 84 months. The key results presented below were measured between 4.4 weeks and 4 months. It is important to note that we have very low certainty in the evidence for all comparisons and outcomes assessed. There may be little to no difference in self-reported joint pain when chewing between occlusal splint (FHSS) and placebo (non-occlusal splint) (RR 1.88, 95% CI 0.94 to 3.75; 1 study, 60 participants with mixed TMD), or pharmacological therapy (diclofenac) (RR 2.10, 95% CI 0.83 to 5.30; 1 study, 29 participants with osteoarthritis), but the evidence is very uncertain. Occlusal splint (FHSS) may reduce muscle pain when chewing compared to no treatment (MD -1.97, 95% CI -2.37 to -1.57; 1 study, 84 participants with disc displacement without reduction), but may have little to no effect when compared to physical therapy (low-level laser) (RR 0.17, 95% CI 0.02 to 1.26; 1 study, 40 participants) or acupuncture (with needles) (MD 0.10, 95% CI -0.80 to 1.00, 1 study, 40 participants) in people with myofascial pain TMD, but the evidence is very uncertain. There may be little to no difference in muscle pain at rest when occlusal splint (FHSS) is compared to no treatment (MD -11.63, 95% CI -29.37 to 6.11; 1 study, 37 participants) or physical therapy (physiotherapy) (MD -0.19, 95% CI -1.25 to 0.87; 1 study, 72 participants) in myofascial pain TMD, but the evidence is very uncertain. There may be little to no difference in severity of joint noise when occlusal splint (FHSS) is compared to no treatment, but the evidence is very uncertain (MD -0.58, 95% CI -7.09 to 5.93; 1 study, 20 participants). When FHSS is compared to physical therapy (specifically, orofacial myofunctional therapy), physical therapy may reduce severity of joint noise, but the evidence is very uncertain (MD 5.92, 95% CI 0.18 to 11.66; 1 study, 20 participants with mixed TMD). There may be little to no difference in frequency of joint noise when occlusal splint (FHSS) is compared to placebo (non-occlusal splint) (RR 1.18, 95% CI 0.63 to 2.20; 1 study, 60 myofascial pain TMD participants), occlusal splint with a different mechanism of action (RR 0.80, 95% CI 0.07 to 9.18; 1 study, 9 participants with disc displacement with reduction), or physical therapy (jaw exercise) (RR 1.50, 95% CI 0.32 to 6.94; 1 study, 18 participants with myofascial pain TMD), but the evidence is very uncertain. Discomfort and recurrence rate were not reported in any study. We judged the certainty of the evidence to be very low for all outcomes in all comparisons due to limitations in study design and imprecision.

AUTHORS' CONCLUSIONS

This review included 57 RCTs with 2846 participants, but the final results are inconclusive, so the research questions remain unanswered. Occlusal splints of the FHSS type may reduce muscle pain when chewing compared to no treatment, but the evidence is very uncertain. Orofacial myofunctional therapy may reduce severity of joint noise compared to occlusal splint (FHSS), but the evidence is very uncertain. For all other comparisons and outcomes, there may be little or no difference between groups, although the evidence is also very uncertain for these findings. Overall, we found insufficient evidence to reach conclusions regarding the effectiveness of occlusal interventions for managing symptoms of TMD, despite the available studies including almost 3000 participants. To make a useful contribution to the debate about the best way to treat TMD, any further research must be well-designed, with enough participants to reach the optimal information size for meaningful results; it requires recruitment from primary care, consensus around key outcomes and measures, and, ideally, long-term follow-up of three to five years, plus inclusion of a cost-effectiveness component.

Effectiveness of Ultrasound Therapy, TheraBite Device, Masticatory Muscle Exercises, and Stabilization Splint for the Treatment of Masticatory Myofascial Pain: A Randomized Controlled Trial

BACKGROUND

Myofascial pain syndrome (MPS) is a particular type of temporomandibular joint disorder. Research findings comparing various treatment approaches are scarce and controversial. Therefore, this study aimed to compare the effectiveness of ultrasound therapy, stabilization splint, TheraBite device, and masticatory muscle exercises in reducing pain intensity and improving mandibular mobility in patients with MPS.

METHODS

It was a single-blind, randomized, parallel-group, active-controlled trial that took place between April 2023 and October 2023 at the Department of Fixed Prosthodontics, Damascus University. Patients older than 18 years old with myofascial pain accompanied by limited jaw opening and pain lasting for at least 6 months were included. Eighty patients were randomly assigned into four groups using online randomization software: ultrasound therapy, stabilization splint, TheraBite device, and masticatory muscle exercises. Only outcome assessors were masked to treatment allocation. The exercise regimen was the exercise program for patients with TMD. The following primary outcome measures were considered at the baseline (t0), at the first (t1), second (t2), and fourth (t3) week of treatment, and at the second (t4) and fifth (t5) month of follow-up: pain intensity using the visual analogue scale, maximum interincisal opening, right lateral movement, and left lateral movement measured in millimeters.

RESULTS

The pain level changed from severe to mild at t3 in ultrasound therapy, stabilization splint, and TheraBite device groups. In the masticatory muscle exercises group, it changed to moderate, with a significant difference between ultrasound therapy (p = 0.012) and stabilization splint (p = 0.013) groups. In addition, the mandibular mobility continued to improve at the subsequent follow-up periods (t4 and t5).

CONCLUSIONS

All therapies are equally effective after 5-month follow-up. However, ultrasound therapy and stabilization splints have the benefit of achieving rapid improvement.

TRIAL REGISTRATION

ISRCTN20833186.

Effectiveness of Occlusal Splint Therapy in Moderating Temporomandibular Joint Disorders With Joint Displacement: A Retrospective Analysis Using Cone Beam Computed Tomography

Background Temporomandibular joint disorders (TMD) represent a prevalent group of conditions impacting the temporomandibular joint. Among the therapeutic interventions, occlusal splint therapy has gained recognition for its potential to address TMD symptoms, particularly in cases involving joint displacement. Objective This study aims to investigate the effectiveness of occlusal splint therapy in cases of moderate TMD with joint displacement, focusing on changes in condylar position, joint morphology, and patient-reported outcomes. Methods A retrospective analysis was conducted involving 148 participants who underwent occlusal splint therapy between January 2018 and December 2020. Data were collected through cone beam computed tomography (CBCT) imaging for precise assessments of condylar position and joint morphology. Ethical approval was obtained, and participants provided informed consent. Baseline characteristics, medical history, and TMD severity were recorded. Occlusal splint therapy included individualized fabrication, occlusal analysis, adjustments for optimal fit, and prescribed wear schedules. Follow-up included CBCT scans at specified intervals (three months and six months), with participant-reported outcomes collected. The data analysis was conducted using IBM SPSS Statistics for Windows, Version 22.0 (Released 2013; IBM Corp., Armonk, NY, USA). Paired t-tests or nonparametric equivalents were employed to assess changes in condylar position and joint morphology. Subgroup analyses were conducted to explore potential factors influencing treatment outcomes. The significance level was set at p < 0.05 for all statistical tests. Results The entire cohort (n = 148) had a mean age of 32.5 years (± 8.1), with a balanced gender distribution. Changes in condylar position revealed a statistically significant improvement (p = 0.03), with a mean decrease of 0.2 mm posttreatment. Joint morphology changes indicated increased joint space width (p = 0.01), improved disc position (p = 0.02), and nonsignificant alterations in bony structures (p = 0.10). Patient-reported outcomes demonstrated significant improvements in pain levels, jaw functionality, and satisfaction (all p < 0.001). Age and gender subgroup analyses showed consistent improvements in condylar position, joint morphology, and patient-reported outcomes across different groups. Conclusion Occlusal splint therapy demonstrated effectiveness in improving condylar position, joint morphology, and patient-reported outcomes in cases of moderate TMD with joint displacement. The findings underscore the potential of occlusal splint therapy as a viable intervention for managing TMD, providing valuable insights for clinicians and researchers.

Effectiveness of anterior repositioning splint versus other occlusal splints in the management of temporomandibular joint disc displacement with reduction: A meta-analysis

BACKGROUND

Disc displacement with reduction (DDwR) is among the common disc disorders of temporomandibular joint (TMJ), which can be managed conservatively by splint therapy. Anterior repositioning splint (ARS) is the most commonly prescribed splint by dental practitioners, but not getting a normal disc-condyle relationship always and other side effects lead to need of comparing with other occlusal splints. This review will help in informed decision-making by clinicians in choosing an appropriate splint type for patients.

AIM

The aim is to compare the effectiveness of ARS in the management of DDwR with other occlusal splints for TMJ and muscle pain, TMJ noise, any adverse effects, regaining normal disc-condyle relationship.

MATERIALS AND METHODS

We followed published protocol in the International prospective register of systematic reviews. Databases were searched till May 2023 using different search strategies as per the database. Title and abstract screening, followed by full-text screening and data extraction with risk of bias, was done by two independent reviewers in Covidence. Outcomes were reported as risk ratio (RR) or mean difference (MD) for dichotomous or continuous outcomes, respectively, using RevMan 5.4 (Review Manager 5.4) software. We used a random effect model for statistical analysis. Certainty of evidence was assessed using the Grading of Recommendation, Assessment, Development, and Evaluation Guideline Development Tool (GRADEpro GDT) software.

RESULTS

A total of 1145 reports were found from a database search. After screening, four studies were included for systematic reviews. Other occlusal splints reported were sagittal vertical extrusion device and mandibular ARS, full hard stabilization splint of canine or centric stabilization type. Data of only two studies could be used for meta-analysis having 30 participants received ARS and 40 received other occlusal splints. We did not find evidence of any difference between ARS and other occlusal splints for TMJ clicking in short term (RR 1.25, 95% confidence interval [CI] 0.91-1.72) but a small difference in favor of other occlusal splint in long term (RR 2.40, 95% CI 1.04-5.55). No evidence of any difference was found between both treatments for TMJ pain in short term (MD-5.68, 95% CI-17.31-5.95) and long term (MD 0.00, 95% CI-2.86-2.86) and muscle pain in short term. The certainty of evidence for comparison of two treatments for different outcomes was of low or very low level.

CONCLUSION

Evidence is uncertain that other occlusal splints reduced TMJ clicking slightly in comparison to ARS. For the remaining outcomes, no evidence of any difference was found between the two splints and it may be biased due to selection bias, inadequate blinding of participants, and outcome assessor.

Efficiency of occlusal splint therapy on orofacial muscle pain reduction: a systematic review

BACKGROUND

This systematic review aims to examine the existing original studies to determine the effectiveness of occlusal splints (OSs) in the management of orofacial myalgia and myofascial pain (MP) in comparison with no treatment or other interventions.

MATERIALS AND METHODS

Based on the inclusion and exclusion criteria of this systematic review, randomized controlled trials were qualified, in which the effectiveness of occlusal splint therapy in the management of muscle pain was examined in comparison with no treatment or other interventions. This systematic review was conducted according to the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analysis 2020. The authors searched three databases (PubMed, CINAHL (The Cumulative Index to Nursing and Allied Health Literature) and Scopus) for English publications published between January 1, 2010, and June 1, 2022. The last database search was carried out on June 4, 2022. Data were extracted from the included studies and assessed for risk of bias using the revised Cochrane risk-of-bias tool for randomized trials.

RESULTS

Thirteen studies were identified for inclusion in this review. In total, 589 patients were diagnosed with orofacial muscle pain who underwent education and various forms of therapy including different types of OSs, light emitting diode therapy, acupuncture, low-level laser therapy, device-supported sensorimotor training, Kinesio Taping, myofunctional therapy, and physical therapy. All studies included demonstrated a high risk of bias.

CONCLUSIONS

There is insufficient evidence regarding whether OS therapy in the treatment of orofacial myalgia and MP offers an advantage over other forms of interventions or no treatment. Further reliable clinical studies in this area are needed to improve the quality of research, which should be performed with larger groups of blinded respondents and controls.

CLINICAL RELEVANCE

Due to the large-scale nature of orofacial muscle pain, it is assumed that each dental clinician will meet patients with orofacial muscle pain repeatedly in daily practice; hence, the review of the effectiveness of OSs in the management of orofacial myalgia and MP is necessary.

Comparison of imaging findings of 714 symptomatic and asymptomatic temporomandibular joints: a retrospective study

BACKGROUND

The correlation between temporomandibular disorders (TMD) and imaging features remains unclear. This study compared the cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI) features in the temporomandibular joints (TMJs) with and without TMD symptoms.

METHODS

The participants were recruited from the TMJ Diagnosis and Treatment Center from March 2022 to September 2022. Condylar morphology and condylar position were evaluated by CBCT. Disc morphology, disc position, and joint effusion were evaluated by T2-weighted image of MRI. The Chi-Square test and binary logistic regression analysis were carried out.

RESULTS

Eighty-two patients with bilateral symptoms, 196 patients with unilateral symptoms, and 79 asymptomatic participants received MRI and CBCT examination. There were significant differences in the distribution of sex, age, condylar morphology, condylar position, disc morphology, disc position, and joint effusion in symptomatic and asymptomatic TMJs (P < 0.05), which showed a positive correlation with symptoms (P < 0.05). In multiple logistic regression, 19-30-year-age group, > 30-year-age group, abnormal condylar morphology, posterior condylar position, disc displacement with reduction (DDWR), and disc displacement without reduction (DDWoR) were found to be statistically significant (P < 0.05). The odds of having symptomatic TMJ were 1.952 higher in the 19-30-year-age group and 1.814 higher in the > 30-year-age group when compared to those aged ≤ 18-year-age group. The odds of having symptomatic TMJ were 2.360 higher in persons with abnormal condylar morphology when compared to those with normal condylar morphology. The odds of having symptomatic TMJ were 2.591 higher in persons with posterior condylar position when compared to those with the normal condylar position. The odds of having symptomatic TMJ were 2.764 higher in persons with DDWR and 4.189 higher in persons with DDWoR when compared to those with normal disc position. The area under the curve of the model was 0.736 ± 0.019 (95% CI 0.700-0.773, P = 0.000), which indicated that the model has a good fitting effect.

CONCLUSIONS

The imaging findings of TMJs were significantly different between symptomatic and asymptomatic TMJs. TMD is affected by multiple factors including > 19-year-age, abnormal condylar morphology, posterior condylar position, DDWR, and DDWoR, which could be risk factors for the development of TMD symptoms. Trial registration This study was retrospectively registered on 28/03/2022 and endorsed by the Ethics Committee of Affiliated Stomatology Hospital of Guangzhou Medical University (LCYJ2022014).